The present invention relates to barrier movement operators and, more particularly, to such operators which respond to both rolling access codes and fixed access codes.
Automatic garage door openers comprise a door or barrier moving unit such as a controlled motor and intelligent activation and safety devices. The barrier moving unit is typically activated in response to an access code transmitted from a remote transmitter. RF signaling is the most common means of transmitting the access codes. It is important that the access code format transmitted by the remote transmitter is the same format as that expected by the receiver of the actuation equipment. A standard access code may, for example, comprise 20 digits which remain unchanged until the door opening equipment is reprogrammed. A possible security problem exists with fixed codes, since a potential thief might intercept and record a standard fixed access code. Later, the thief could return with a trans\7mitter for producing an identical duplicate of the recorded code and open the barrier without permission. Some garage door opening systems have begun using codes to activate the system which change after each transmission. Such varying codes, called rolling codes, are created by the transmitter and acted on by the receiver, both of which operate in accordance with the same method to predict a next access code to be sent and received.
A modem barrier movement controller, such as a garage door opener, may respond to multiple different types of transmitters or wall controls. For example, such a system may respond to a portable rolling code transmitter as might be carried in an automobile, a fixed wall control which is wired to a barrier controller and to an external keypad transmitter which is attached outside the area to be closed by a movable barrier. Such a keypad transmitter can be accessed by the general public and accordingly, should provide good protection against improper use. One such keypad is described in U.S. Pat. No. 5,872,513 issued Feb. 16, 1999 to the Chamberlain Group, Inc. The keypad transmitter described in U.S. Pat. No. 5,872,514 uses a rolling code format which incorporates digits entered by user interaction with a keypad into the transmitted rolling code. A receiver of the barrier movement controller then properly validates the rolling code which may include the keypad digits and performs requested barrier operations.
The keypad type transmitter requires that a user type in a passcode then press a key to initiate the transmission of the rolling code including the typed in digits. This is a difficult task to perform when the user has his or her arms full of items, such as groceries, but wants to gain access to the closed area. What is need is a secure transmitter which permits hands free operation to send enabling security codes to the controller of a barrier movement operator.